JP4243635B2 - Lighting device - Google Patents

Description

  The present invention relates to a lighting device, and particularly relates to a large-sized lighting device that requires high luminance.

  In recent years, display units have been used in large quantities in word processors, personal computers, and the like due to expansion of display capacity or improvement in characteristics. Furthermore, a thin and light display unit having a large screen size for a workstation from a notebook is required, and a high-luminance and high-efficiency lighting device is desired for colorization.

  Conventionally, the edge-light type backlight used in the liquid crystal display device is made to make light incident from the side surface of the light guide plate, and the internal propagation light by total reflection is totally reflected by the light guide plate and white ink etc. whose central part is inclined. Was broken and emitted to the light emitting surface side.

  FIG. 40 is an explanatory diagram of a conventional edge light type illumination device.

  In the figure, 81 is a fluorescent tube serving as a light source, 82 is a light guide plate made of transparent resin, 82a is an incident surface of the light guide plate 82, 82b is a back surface of the light guide plate 82 on which a diffuse reflection pattern is printed, and 82c is a light guide plate 82. , 83 is a reflecting sheet, 84 is a light emitting surface, 85 is a reflecting mirror provided so as to surround the fluorescent tube 81, 86 is a linear prism, 87 is a diffusion sheet, 88 is internally propagated light, and 89 is emitted light. There is a lighting device 90 comprising them.

  As shown in the figure, in the conventional edge light type backlight, a fluorescent tube 81 surrounded by a reflecting mirror 85 is arranged so that the emitted light is incident from an incident surface 82 a of the light guide plate 82, and the light guide plate 82. The emission surface 82c is inclined from both ends toward the central portion so that the thickness thereof becomes thinner toward the central portion. Then, a diffuse reflection pattern with white ink or the like is provided on the back surface 82b of the light guide plate 82 so as to increase the printing area as the distance from the fluorescent tube 81 increases, and the diffuse reflection pattern is scattered on the back surface of the back surface 82b. A reflection sheet 83 for effectively emitting light rays is disposed. Further, a linear prism 86 for collecting the outgoing light 89 in the normal direction is provided on the light emitting surface 84 above the light guide plate 82, and the diffuse reflection pattern on the back surface 82 b is visually recognized on the outgoing direction side of the linear prism 86. A diffusion sheet 87 is arranged so as not to be formed, and an edge light type illumination device 90 is configured.

  In this conventional edge light type illumination device 90, the diffused light emitted from the fluorescent tube 81 enters from the incident surface 82a of the light guide plate 82, and propagates through the light guide plate 82 while satisfying the total reflection condition. Since the outgoing surface 82c of the light guide plate 82 is inclined toward the central portion, the internal propagation light 88 becomes steeper by the inclination angle θ of the outgoing surface 82c every time it is totally reflected by the outgoing surface 82c, and the critical angle. If it becomes above, it will become the emitted light 89, and is radiate | emitted from the output surface 82c, On the other hand, the propagation light 88 which was totally reflected by the output surface 82c and reached the back surface 82b will be radiate | emitted from the light emission surface 84 because a total reflection condition collapse | crumbles by a diffuse reflection pattern. It is like that.

  The conventional edge light type illumination device does not emit all the light rays emitted from the fluorescent tube and diffusely reflected by the diffuse reflection pattern to the light emitting surface side, but part of the light is repeatedly propagated to the opposite fluorescent tube. The current situation is that light loss occurs due to collision. In order to reduce this phenomenon, an attempt has been made to improve the light guide plate by providing an inclination on the exit surface of the light guide plate and reducing the thickness of the light guide plate toward the center, but it is still insufficient and the light utilization rate is low. There was a problem.

  In order to effectively improve the luminance in the normal direction, a linear prism plate is arranged between the light guide plate and the diffuser plate. The prism pitch of the linear prism plate and the matrix display panel If the pitch between the electrodes is not optimum, interference occurs. Therefore, a diffusion plate having a high diffusion degree is used, or an optimum pitch is set for each model to reduce the occurrence of interference. However, when the diffusivity is increased, the luminance in the normal direction decreases, and when a linear prism mold suitable for each model is manufactured, the cost increases.

  Accordingly, an object of the present invention is to realize a thin and lightweight high-efficiency lighting device having high luminance and uniform luminance distribution.

The present invention comprises a plurality of unit units including a light source and a light guide plate,
The light guide plate includes an incident surface on which a light beam emitted from the light source is incident, a reflective surface that reflects the incident light beam, a side surface that is substantially parallel to the reflective surface, and an output beam that emits the incident light beam. And the reflective surface is inclined with respect to the exit surface,
Each of the light guide plates has the same shape,
Each of the unit units is arranged in the same direction,
The light source of the second unit unit adjacent to the first unit unit is disposed behind the emission surface of the first unit unit, and the first unit unit and the second unit unit are Are adjacent to each other without providing a step .

  According to the present invention, it is possible to realize a high-luminance and thin illuminating device having a high light beam utilization rate.

  The best mode for carrying out the invention will be described below.

  FIG. 1 is a block diagram showing the principle related to the present invention.

  In the figure, 1 is a light source, 2 is a light guide plate, 2a is an entrance surface of the light guide plate 2, 2b is a back surface of the light guide plate 2, 2c is an exit surface of the light guide plate 2, 3 is a reflection surface, 3a is a reflection surface 3 A side wall surface facing the light source 1, 4 is a light emitting surface, and 5 is a space.

  As shown in the figure, the illuminating device according to the present invention includes a light source 1, a light guide plate 2 having a light incident surface 2 a on which light rays from the light source 1 are incident, and an output surface 2 c from which incident light rays are emitted, and a light guide plate. 2, the light guide plate 2 is disposed on the side of the light guide plate 2, and the light guide plate 2 is disposed on the side of the light guide plate 2. As the distance from the light source 1 is increased, the light exit surface 2c is formed so that the thickness of the light guide plate 2 is reduced, and the reflective side surface 3a that opposes the light source 1 with the light guide plate 2 of the light guide plate 2 and the reflective surface 3 interposed therebetween. A space portion 5 sandwiched between the reflecting surface 3 and the light emitting surface 4 is formed between the two.

  Furthermore, the exit surface 2c of the light guide plate 2 is composed of a plurality of continuous planes having different inclination angles with the back surface 2b, and the inclination angle of the plane on the tip side of the light guide plate 2 is larger than the inclination angle of the plane on the incident surface 2a side. It is characterized by that.

  Furthermore, the incident surface 2a of the light guide plate 2 is a diffusing surface provided with unevenness.

  Furthermore, the back surface 2b of the light guide plate 2 is a diffusing surface.

  Furthermore, the exit surface 2c of the light guide plate 2 is a diffusing surface.

  Further, a transparent diffusion sheet is disposed between the back surface 2b of the light guide plate 2 and the reflection surface 3.

  Furthermore, the reflecting surface 3 is an uneven surface.

  Further, at least one linear prism plate for converging outgoing light in the normal direction is provided on the light emitting side of the light emitting surface 4, and at least one of the linear prism plates emits light in the axial direction of the linear prism plate. The display device arranged on the surface 4 is arranged such that the relative position with respect to the direction of the matrix electrode pattern is not parallel or orthogonal.

  Further, as another aspect of the lighting device according to the present invention, the lighting device according to the present invention is composed of a plurality of unit units, and a plurality of light emitting surfaces 4 of each unit unit are arranged on the same plane. The unit units are arranged in a plane.

  Further, as yet another aspect of the lighting device according to the present invention, the lighting device according to the present invention is composed of a plurality of unit units, and a plurality of the unit unit reflecting surfaces 3 and light emitting surfaces 4 are adjacent to each other. These unit units are stacked, and the side wall surface 3a side of the unit unit is used as a light emitting surface.

  FIG. 2 is an explanatory view of the operation of the lighting device related to the present invention.

  In the figure, 1 is a light source, 2 is a light guide plate for propagating light from the light source, 2a is an incident surface of the light guide plate 2 on which light from the light source is incident, 2b is a back surface of the light guide plate 2, and 2c is a light guide plate 2. The exit surface from which the light propagating through the light guide plate 2 is emitted is formed so that the angle formed with the back surface b is θ so that the wall thickness decreases as the distance from the light source 1 increases, 3 is the back surface 2b of the light guide plate 2 3a is a side wall surface of the reflective surface 3 facing the light source 1 with the light guide plate 2 interposed therebetween, and 4 is a light guide plate 2 that receives the light from the light source 1. A light emitting surface that emits light through 5, 5 is a space where the light emitting surface 2 c, the reflecting surface 3, the side wall surface 3 a, and the light emitting surface 4 are sandwiched, 6 surrounds the light source 1, and the light from the light source 1 enters the incident surface 2 a of the light guide plate 2. Reflecting mirror 7 reflecting in the direction, 7 is the internally propagating light that is incident from the incident surface 2a and propagates inside the light guide plate 2, 8 is A emission light emitted from the emitting surface 2c After propagated inside the optical plate, 10 denotes an illumination device composed of these.

  As shown in the drawing, in the illumination device 10 according to the present invention, the light emitted from the light source 1 is reflected by the reflecting mirror 6, and the light that repeats multiple reflections with the light source 1 and the direct light are combined to form the light guide plate 2. Incident from the input surface 2a.

  Here, the light incident on the light guide plate 2 is incident at about ± 42 ° with respect to the normal of the incident surface according to Snell's law, and the surface of the light guide plate is perpendicular to the incident surface. The angle of the light beam reaching the angle is about ± 48 ° or more with respect to the normal of the surface of the light guide plate, and is totally reflected and propagates inside the light guide plate. Therefore, when the surface of the light guide plate is a plane perpendicular to the incident surface, all the propagating light is emitted from the end surface facing the light source of the light guide plate.

  However, the light guide plate 2 of the illuminating device 10 according to the present invention is formed such that the exit surface 2c is inclined with the angle formed with the back surface 2b being θ, so that the thickness of the light guide plate 2 decreases as the distance from the light source 1 increases. Therefore, the propagating light 7 incident from the incident surface 2a is steep at an angle of the inclination angle θ with respect to the output surface 2c every time it is totally reflected by the output surface 2c. While the reflection is repeated, a part of the propagation light 7 is emitted from the emission surface 2 c as the emission light 8 toward the light emitting surface 4, and a part of the propagation light 7 is repeatedly propagated as the propagation light 7. Further, the propagating light 7 is partially emitted from the back surface 2b, but is reflected toward the light emitting surface 4 by the reflecting surface 3 facing the back surface 2b.

  Moreover, the outgoing light 8 emitted from the front end side of the light guide plate 2 reaches the light emitting surface 4 directly, or the light emitted from the light emitting surface 4 after being reflected by the side wall surface 3a of the reflecting surface 3 without reaching directly. There is.

  Here, when the reflective side surface is provided adjacent to the end of the light guide plate away from the light source, the amount of light reflected by the reflective side surface increases, leading to an increase in the light loss rate, A difference in luminance distribution occurs because the light beam that directly reaches the light-emitting surface after being emitted from the light plate and the light beam that reaches the light-emitting surface after being reflected by the reflecting side surface overlap at a portion slightly inside the edge of the light-emitting surface. .

  However, in the illuminating device 10 according to the present invention, a gap is provided between the front end portion of the light guide plate 2 and the side wall surface 3a, and the light guide plate 2 and the side wall surface 3a are sandwiched between the reflecting surface 3 and the light emitting surface 4. By arranging the space portion 5, most of the emitted light 8 emitted from the emission surface 2 c can be emitted directly in the direction of the emission surface 4, the luminance distribution is made uniform, the light loss is reduced, and high efficiency is achieved.

  3A and 3B are diagrams showing a first embodiment of the lighting device according to the present invention, in which FIG. 3A is a cross-sectional view, and FIG. 3B is a diagram showing a luminance distribution of the lighting device of the present embodiment.

  In FIG. 11A, 11 is a fluorescent tube, 12 is a light guide plate, 12a is an entrance surface of the light guide plate 12, 12b is a back surface of the light guide plate 12, 12c ′ is a first exit surface of the light guide plate 12, and 12c ″ is The second exit surface, 13 is a reflecting surface, 14 is a light emitting surface, 15 is a space portion, 16 is a reflecting mirror, and 20 is an illuminating device composed of them.

  As shown in FIG. 6A, the illumination device of the present embodiment has an incident surface 12a on the light emission side of a fluorescent tube 11 surrounded by a reflecting mirror 16 in a semicircular shape in order to collect emitted light in one direction. The light guide plate 12 is disposed so as to face the light source 11. The light guide plate 12 has an emission surface inclined so that the thickness thereof becomes thinner as the distance from the light source 11 increases, and the emission surface is in contact with the first emission surface 12c ′ having an angle θ1 with respect to the back surface 12b on the light source 11 side. The second exit surface 12c "forms an angle θ2 with respect to the back surface 12b on the front end side, θ2 is larger than θ1 and the boundary between the first exit surface 12c ′ and the second exit surface 12c ″ is It is chamfered and curved. Further, the reflective surface 13 is opposed to the back surface 12 b of the light guide plate 12, the side wall surface 13 a of the reflective surface 13 is disposed on the side facing the light source 11, and the light emitting surface 14 is provided on the side facing the reflective surface 13. Yes. A space is provided between the front end of the light guide plate 12 and the side wall surface 13a, and the space surrounded by the emission surfaces 12c ′ and 12c ″ of the light guide plate 12, the reflection surface 13, the side wall surface 13a, and the light emitting surface 14. A portion 15 is provided.

  As in this embodiment, the shape of the light guide plate 12 is such that the inclination angle θ1 of the first emission surface 12c ′ on the light source 11 side with respect to the back surface 12b and the inclination angle θ2 of the second emission surface 12c ″ on the tip side with respect to the back surface 12b. And the angle of θ2 is made larger than θ1, so that the emitted light can be appropriately dispersed and emitted without being concentrated on the tip portion, so that the light utilization rate is improved and the light emitting surface is improved. 14 The luminance distribution at the end can be made uniform, and the light guide plate 12 can be processed more easily than the one with a sharp tip, and the yield can be improved because damage to the tip is reduced and handling is easy. Can do.

  FIG. 6B is a diagram showing the luminance distribution when the angle θ2 is constant and the angle θ1 is changed (assuming θ2> θ1) in the illumination device of the present embodiment, and the solid line 401 has a small angle θ1. A broken line 402 indicates a case where the angle θ1 is large.

  As shown in the figure, when the angle θ1 is small, the amount of light emitted from the first emission surface 12c ′ is small and propagates to the front end side of the light guide plate 12, so that the amount of light emitted from the front end side is large and the luminance is high. However, when the angle θ1 is large, the amount of light emitted from the first emission surface 12c ′ increases, while the amount of light emitted from the second emission surface 12c ″ decreases, so that the luminance distribution becomes uniform. However, the luminance distribution on the tip side increases or decreases in a similar manner in proportion to the angle θ1.

  The reflecting surface 13 may be a diffusing surface, a mirror surface, or the like. If the reflecting surface 13 is a diffusing surface, the light emitted from the back surface 12b of the light guide plate 12 is diffused, so the amount of light emitted in the vicinity of the light source 11 And the luminance distribution can be made uniform.

  4A and 4B are diagrams showing a second embodiment of the lighting device according to the present invention, in which FIG. 4A is a cross-sectional view, and FIG. 4B is a diagram showing a luminance distribution of the lighting device of the present embodiment.

  In FIG. 2A, 21 is a fluorescent tube, 22 is a light guide plate, 22a is an incident surface of the light guide plate 22, 22b is a back surface of the light guide plate 22 on which a diffuse reflection pattern is printed, and 22c ′ is provided with a shape diffusion portion. The first light exit surface of the light guide plate 22, 22 c ″ is the second light exit surface, 23 is the reflective surface, 24 is the light emitting surface, 25 is the space portion, 26 is the reflecting mirror, and 30 is an illumination composed of them. Device.

  As shown in FIG. 6A, in the illumination device of this embodiment, the shape of the light guide plate 22 is different from that of the first embodiment, and the first emission surface 22c ′ is a flat surface provided with a shape diffusion portion. A diffuse reflection pattern is also printed on the back surface 22b.

  As in this embodiment, the luminance distribution is made uniform by providing the back surface 22b and the first light exit surface 22c ′ with a diffused reflection pattern printed with a shape diffusing portion having a concavo-convex surface or white paint. Can do.

  Here, the positions where the shape diffusing portion and the diffuse reflection pattern are provided are not limited to the back surface 22b and the first emission surface 22c ′, respectively, and the shape diffusing portion is provided on the back surface 22b or the diffuse reflection pattern is the first. It is possible to provide it on the exit surface 22c ′. Furthermore, the diffusion printing pattern can improve the luminance distribution by weighting to change the printing area according to the distance from the light source, but when the illumination device is relatively small and the inclination angle of the exit surface of the light guide plate is large, It does not matter if weighting is not performed.

  FIG. 6B is a diagram showing a luminance distribution when a weighted diffuse reflection pattern is printed only on the back surface 22b of the light guide plate 22 in the illumination device of the present embodiment. The luminance distribution due to the light rays emitted from the emission surface 22c ′, the one-dot chain line 404 is the luminance distribution due to the light rays emitted from the second emission surface 22c ″, and the solid line 405 is the overall luminance distribution synthesized by them.

  As shown in the figure, it can be seen that when a weighted diffuse reflection pattern is provided on the back surface 22b, the luminance distribution is made uniform. By adopting the configuration shown in this embodiment, the light utilization rate is high, and the luminance distribution is also A uniform lighting device can be obtained.

  FIG. 5 is a diagram showing a third embodiment of the illumination device according to the present invention.

  In the figure, 31 is a fluorescent tube, 32 is a light guide plate, 32a is an incident surface of the light guide plate 32 provided with an uneven surface whose axis is parallel to the fluorescent tube 31, 32b is a back surface of the light guide plate 32, and 32c 'is a light guide plate. 32 is a first exit surface, 32c ″ is a second exit surface of the light guide plate 32, 33 is a reflective surface, 34 is a light emitting surface, 35 is a space portion, 36 is a reflecting mirror, and 37 is a diffuse reflection pattern. Reference numeral 40 denotes a transparent diffuse reflection sheet. Reference numeral 40 denotes an illuminating device including them.

  As shown in the figure, the illumination device of the present embodiment is different from the first and second embodiments in the shape of the light guide plate 32, and the wave shape whose axis is parallel to the fluorescent tube 31 on the incident surface 32 a of the light guide plate 32. An uneven surface is provided. Further, a transparent diffuse reflection sheet on which a diffuse reflection pattern is printed is provided on the back surface 32 b side of the light guide plate 32 between the back surface 32 b and the reflection surface 33.

  The present embodiment is suitable for a relatively small backlight, and the wave-like uneven surface whose axis is parallel to the fluorescent tube 31 is provided on the incident surface 32a. Therefore, the propagation direction of the light incident from the incident surface 32a is It is possible to set the angle of incidence to about ± 42 ° or more with respect to the normal line when the incident surface 32a is perpendicular to the back surface 32b. Therefore, it is possible to increase the amount of emitted light in the vicinity of the fluorescent tube 31. Further, the luminance distribution can be made uniform by the diffuse reflection sheet 37 provided between the back surface 32 b and the reflection surface 33.

  6A and 6B are views showing a fourth embodiment of the illumination device according to the present invention, in which FIG. 6A is a cross-sectional view, and FIG. 6B is a plan view for explaining a method of arranging a linear prism plate.

  In the figure, 41 is a fluorescent tube, 42 is a light guide plate, 42a is an entrance surface of the light guide plate 42, 42b is a back surface of the light guide plate 42 on which a diffuse reflection pattern is printed, and 42c 'is a first exit surface of the light guide plate 42. , 42c "is the second exit surface of the light guide plate 42, 43 is the reflecting surface, 43a is the side wall surface of the reflecting surface 43, 44 is the light emitting surface, 45 is the space, 46 is the reflecting mirror, 47 is the linear prism plate, 48 Is a diffusion sheet, and 50 is an illuminating device composed of them.

  As shown in the figure, the illumination device of this embodiment is different from the first to third embodiments in the shape of the reflection surface 43 and the side wall surface 43a of the reflection surface 43, and the reflection surface 43 and the side wall surface 43a are orthogonal to each other. Instead, the reflecting surface 43 and the side wall surface 43a are continuously formed as curved surfaces. Furthermore, a weighted diffuse reflection pattern is printed on the back surface 32b of the light guide plate 32, and a linear prism plate 47 for giving directivity in the normal direction to the emitted light on the light emitting surface 44. And the axial direction of the matrix electrodes of the display device (not shown) arranged on the upper side are arranged so as not to be orthogonal or parallel to each other. In addition, a diffusion sheet 48 is disposed on the linear prism plate 47 so that the diffusion print pattern printed on the back surface 42b of the light guide plate 42 is not visually recognized.

  When the reflecting surface 43 and the side wall surface 43a are formed as a continuous curved surface as in this embodiment, the loss of light emitted from the light guide plate 42 is reduced, the light utilization rate is improved, and the luminance distribution is made uniform. Can do.

  FIG. 6B is a plan view for explaining the arrangement method of the linear prism plate 47. The prism shaft 47a of the linear prism plate 47 is parallel to any of the orthogonal matrix electrodes 49a and 49b of the display device, or It is arranged so that the inclination is an angle φ (0 ° <φ <90 °) so as not to be orthogonal. By disposing the linear prism plate 47 in this way, it is possible to prevent display image quality from being deteriorated due to interference.

  7A and 7B are diagrams (part 1) illustrating directivity characteristics of the light guide plate, where FIG. 7A is a perspective view, and FIG. 7B is a diagram illustrating a relationship between a light emission angle and relative luminance.

  In FIG. 5A, 51 is a fluorescent tube serving as a light source, 52 is a light guide plate disposed on the side of the fluorescent tube 51, 52a is an incident surface of the light guide plate 52 facing the fluorescent tube 51, and 52b is a light guide plate. The back surface of 52, 52c is the exit surface of the light guide plate 52 that forms an angle θ with the back surface 52b, 54 is a reflector provided so as to surround the fluorescent tube 51, 58 is the propagation light inside the light guide plate 51, 59 is the exit surface 59c. The angle θ is set to 10 °. Hereinafter, components having the same functions are denoted by the same reference numerals, and description thereof is omitted.

  In the figure, the light source is composed of only a fluorescent tube 51, a reflecting mirror 54 surrounding the fluorescent tube 51, and a light guide plate 52, and no reflecting surface or the like is provided.

  FIG. 5B is a diagram showing the directional distribution characteristics between the front end side of the light guide plate and the light source side in this case. The solid line 406 indicates the characteristics on the front end side, and the broken line 407 indicates the characteristics on the light source side.

  As shown in the figure, when no reflecting surface or the like is provided, the directivity width hardly changes on the tip side and the light source side, but as shown by the broken line 407, the emitted light quantity on the light source side is small and the angle is small. It turns out that there are many ingredients.

  FIGS. 8A and 8B are diagrams (part 2) illustrating the directivity characteristics of the light guide plate. FIG. 8A is a perspective view, and FIG. 8B is a diagram illustrating the relationship between the light emission angle and the relative luminance.

  In FIG. 5A, reference numeral 53 denotes a reflecting surface disposed below the light guide plate 52 so as to face the back surface 52b. Further, the angle θ is set to 10 °.

In the drawing, a fluorescent tube 51 serving as a light source, a reflecting mirror 54 surrounding the fluorescent tube 51, a light guide plate 52, and a reflecting surface 53 provided below the light guide plate 52 are shown. It is a figure which shows each directional distribution characteristic in case the reflective surface 53 is a mirror surface, and a diffused reflective surface, The solid line 408 shows the characteristic in case the reflective surface 53 is a mirror surface, and the broken line 409 shows the reflective surface 53 as a diffuse reflective surface. The characteristic in the case of is shown.

  As shown in the figure, when the reflecting surface 53 is a mirror surface, the luminance peak is not different from the case where no luminance peak is provided as indicated by the solid line 408, but the directivity width is increased. Recognize. This is because the light beam emitted from the back surface 52b of the light guide plate 52 is steeper and emitted by an angle θ formed by the emission surface 52c and the back surface b. Further, when the reflecting surface 53 is a diffuse reflecting surface, the luminance peak decreases as shown by the broken line 409, but the directivity width is increased. This is because the emitted light 59 is distributed and emitted from each part of the emission surface 52c, and the luminance distribution on the light emitting surface is improved.

  FIGS. 9A and 9B are diagrams showing the directivity characteristics of the light guide plate (No. 3). FIG. 9A is a perspective view, and FIG. 9B is a diagram showing the relationship between the light emission angle and the relative luminance.

  In FIG. 2A, reference numeral 55 denotes a transparent diffuse reflection sheet on which a weighted diffuse reflection pattern is printed, which is disposed between the back surface 52b of the light guide plate 52 and the reflection surface 53. Further, the angle θ is set to 10 °. In the drawing, a fluorescent tube 51 serving as a light source, a reflecting mirror 54 surrounding the fluorescent tube 51, a light guide plate 52, a reflecting surface 53 including a mirror surface, and a back surface 52b of the light guiding plate 52 and a reflecting surface 53 are disposed. And a diffuse reflection sheet 55.

  FIG. 6B is a diagram showing the directional distribution characteristic when the diffuse reflection sheet 55 is disposed between the rear surface 52b of the light projecting plate 52 and the reflective surface 53 formed of a mirror surface, and the characteristic is shown by a solid line 410. ing. As shown in the figure, when the diffuse reflection sheet 55 is disposed between the back surface 52b of the light guide plate 52 and the reflection surface 53, it is the same as the broken line 409 when the reflection surface 53 in FIG. In addition, as indicated by the solid line 410, the luminance peak decreases, but the width of directivity increases. This is because the emitted light 59 is distributed and emitted from each part of the emission surface 52c, and the luminance distribution on the light emitting surface is improved.

  10A and 10B are diagrams showing the directivity characteristics of the light guide plate (No. 4). FIG. 10A is a perspective view, and FIG. 10B is a diagram showing the relationship between the light emission angle and the relative luminance.

  In FIG. 5A, reference numeral 56 denotes an uneven surface facing the light guide plate 52 so that the axial direction is parallel to the longitudinal direction of the fluorescent tube 51 between the back surface 52b of the light guide plate 52 and the reflection surface 53. It is a linear prism plate arranged. Further, the angle θ is set to 10 °. In the drawing, a fluorescent tube 51 serving as a light source, a reflecting mirror 54 surrounding the fluorescent tube 51, a light guide plate 52, a reflecting surface 53 including a mirror surface, and a back surface 52b of the light guiding plate 52 and a reflecting surface 53 are disposed. And a linear prism plate 56.

  FIG. 5B is a diagram showing the directional distribution characteristic when the linear prism plate 56 is disposed between the back surface 52b of the light guide plate 52 and the reflecting surface 53 formed of a mirror surface, and the characteristic is shown by a solid line 411. ing. As shown in the figure, when the linear prism plate 56 is disposed between the back surface 52b of the light guide plate 52 and the reflecting surface 53, the luminance is improved as shown by the solid line 411, and the emitted light amount on the light source side is reduced. The luminance distribution can be improved.

  FIGS. 11A and 11B are diagrams showing the directivity characteristics of the light guide plate (No. 5). FIG. 11A is a perspective view, and FIG. 11B is a diagram showing the relationship between the emission angle in the upper and horizontal directions of the light beam and the different luminance. FIG.

  In FIG. 5A, the reference numeral 57 denotes an uneven surface facing the light guide plate 52 so that the axial direction is perpendicular to the longitudinal direction of the fluorescent tube 51 between the fluorescent tube 51 and the incident surface 52a of the light guide plate 52. It is a linear prism plate arranged. Further, the angle θ is set to 10 °. In the figure, a fluorescent tube 51 serving as a light source, a reflecting mirror 54 surrounding it, a light guide plate 52, a reflecting surface 53 formed of a mirror surface, and a fluorescent tube 51 and an incident surface 52a of the light guide plate 52 are disposed. And the linear prism plate 57 thus formed.

  FIG. 5B shows the vertical direction (angle α) and the horizontal direction (angle β) with and without the linear prism plate 57 disposed between the fluorescent tube 51 and the incident surface 52a of the light guide plate 52, respectively. The solid line 412 indicates the vertical characteristics when the prism plate 57 is provided, the broken line 413 indicates the vertical characteristics when the prism -357 is not provided, and the solid line 414 indicates the prism plate. The solid line 415 indicates the characteristic in the left-right direction when the prism plate 57 is not provided. As shown in the figure, the light guide plate 52 has an uneven surface between the fluorescent tube 51 and the incident surface 52 a of the light guide plate 52 so that the axial direction of the linear prism plate 57 is perpendicular to the longitudinal direction of the fluorescent tube 51. As compared with the case where the linear prism plate 57 indicated by the broken line 415 is not provided, the characteristic in the left-right direction when arranged toward the side is narrowed down in the left-right direction, and thus the directivity width is reduced. Brightness is improved because the light rays are concentrated.

  12A and 12B are diagrams showing a fifth embodiment of the lighting device according to the present invention, in which FIG. 12A is a plan view, FIG. 12B is a cross-sectional view taken along line AA ′ in FIG. c) The figure is a partial sectional view taken along line BB ′ of FIG.

  In the figure, 61 is a fluorescent tube serving as a light source, 62 is a light guide plate made of a transparent body, 62a is an incident surface of the light guide plate 62, 62b is a rear surface of the light guide plate 62 on which a weighted diffuse reflection pattern is printed, and 62c is a rear surface. 62b is the exit surface of the light guide plate 62 formed at an angle θ, 62d is a reflective side surface at the end of the light guide plate 62, 63 is a reflective surface below the rear surface 62b of the light guide plate 62, and 63a is the central portion of the reflective surface 63. , A light emitting surface, 65 a space portion, 66 a reflecting mirror surrounding the fluorescent tube 61, 67 a linear prism plate, 68 a diffusion sheet, 69 a light shielding portion, and 70 It is the comprised illuminating device.

  As shown in FIGS. 4A and 4B, the lighting device 70 of the present embodiment has a lighting device as shown in the first to fourth embodiments as a unit unit, and a plurality of unit units are planar. The four fluorescent tubes 61 serving as the light source are provided on the four side surfaces surrounded by the reflecting mirror 66, and four independent light guide plates 62 are provided on the side of the fluorescent tube 61 corresponding to each. It is arranged. The shape of each light guide plate 62 is inclined toward the front end side so that the angle formed by the exit surface 62c with the back surface 62b is θ, and the width thereof is also narrowed toward the front end side. A diffuse reflection pattern weighted in consideration of the above is printed. The reflection surface 63 below the back surface 62b of the light guide plate 62 is provided with a quadrangular pyramid-shaped convex reflection surface 63a in a space portion 65 where the tips of the four light guide plates 62 at the center face each other. On the light emitting surface 64, a linear prism plate 67 is disposed so that the axial direction of matrix electrodes of a display device (not shown) disposed above the linear prism plate 67 and the axis of the linear prism plate 67 are not orthogonal or parallel to each other. . Further, a diffusion sheet 68 is disposed on the linear prism plate 67 so that the diffuse reflection pattern printed on the back surface 62b of the light guide plate 62 is not visually recognized.

  Further, as shown in FIG. 4C, the four light guide plates 62 are configured so that the light guide plates 62 are independent so that the light propagating in the light guide plate 62 does not return toward the other fluorescent tubes 61. A space is provided between the individual light guide plates 62 to form a light shielding portion 69. The end surface of the light guide plate 52 is provided with a reflective side surface 62d so as not to emit light, and the reflective side surface 62d is inclined so that the reflected light travels toward the light emitting surface 64.

  The illuminating device 70 shown in the present embodiment is suitable for a large-sized illuminating device that requires high luminance. The illuminating device as shown in the first to fourth embodiments is used as a unit unit, and a plurality of unit units are provided. By arranging in a plane, it is possible to obtain a high-luminance lighting device with a high light utilization factor while making the luminance distribution uniform.

  In addition, as in the present embodiment, the configuration in which the light guide plates 62 are separated and the four light guide plates 62 are arranged is advantageous, but even if the light guide plates 62 are integrated without being separated, the efficiency is improved. Will improve to some extent.

  Further, the number of unit units arranged in a planar shape is not limited here, and the configuration thereof can be changed according to the required specifications of the lighting device, such as arranging two unit units facing each other. Furthermore, in this embodiment, a diffuse reflection pattern is printed on the back surface 62b of the light guide plate 62 to achieve uniform brightness distribution. However, the means for uniformizing the brightness distribution is also limited in this embodiment. Instead, it is also possible to use the above-described means shown in FIGS.

  FIG. 13 is a view showing a sixth embodiment of the lighting device according to the present invention, and is a partial sectional view of the lighting device.

  In the figure, 71 is a fluorescent tube, 72 is a light guide plate, 72a is an entrance surface of the light guide plate 72, 72b is an exit surface of the light guide plate 72, 73 is a reflection surface, 74 is a reflection mirror, 75 is a diffusion sheet, 80 Is a lighting device composed of them.

  As shown in the figure, the lighting device 80 of the present embodiment has a plurality of unit units arranged vertically with the lighting devices as shown in the first to fourth embodiments as unit units, and a light guide plate 72 in the unit. The side surface and the reflecting surface 73 are adjacent to each other, and the light emitting surface is a surface facing the fluorescent tube 71. Further, the angle θ formed by the light exit surface 72b of the light guide plate 72 and the reflection surface 73 is 30 °, and the light guide plate 72 is made of acrylic resin. A diffusion sheet 75 is arranged on the light emitting surface side so that the luminance distribution is uniform and the reflecting surface 73 is not visible. Of the emitted light emitted from the emitting surface 72b of the light guide plate 72 of one unit unit, Except for those that directly reach the diffusion sheet 75, the light is reflected by the reflection surface 73 of the adjacent unit unit and proceeds to the diffusion sheet 75.

  The illuminating device 80 shown in the present embodiment is suitable for a large illuminating device that requires high luminance. The illuminating device as shown in the first to fourth embodiments is used as a unit unit, and a plurality of unit units are provided. By arranging vertically, it is possible to obtain a high-luminance lighting device with uniform luminance distribution, high directivity of light rays, and high light utilization factor.

  FIG. 14 is a diagram showing a seventh embodiment of the lighting device according to the present invention, and is a partial sectional view of the lighting device.

  In this figure, 71 ′ is a fluorescent tube, 72 ′ is a light guide plate, 72a ′ is an entrance surface of the light guide plate 72 ′, 72b ′ is an exit surface of the light guide plate 727, 73 ′ is a reflection surface, 74 ′ is a reflection mirror, 75 'Is a diffusion sheet, and 80' is an illuminating device composed of them.

  As shown in the figure, the illumination device 80 ′ of the present embodiment is different from the seventh embodiment in the shape of the light guide plate 72 ′, and the cross-sectional shape of the light guide plate 72 ′ is substantially isosceles triangle, Two exit surfaces 72b 'are provided with the apex angle inserted. The apex angle θ is 30 ° as in the sixth embodiment.

  The illuminating device 80 ′ shown in the present embodiment can be a high-luminance illuminating device with higher light beam directivity and higher light utilization than the sixth embodiment.

  FIG. 15 is a view showing an eighth embodiment of the lighting apparatus according to the present invention, and is a partial sectional view of the lighting apparatus.

  In the figure, 71 "is a fluorescent tube, 72" is a light guide plate, 72a "is an entrance surface of the light guide plate 72", 72b "is an exit surface of the light guide plate 72", 73 "is a reflection surface, 74" is a reflection mirror, Reference numeral 75 "denotes a diffusion sheet, and reference numeral 80" denotes an illuminating device constituted by them.

  As shown in the drawing, the illumination device 80 "of this embodiment differs from the sixth and seventh embodiments in the arrangement method of the unit units, and the side surface of the light guide plate 72" and the reflection surface 73 "in the unit are different. Unit units are stacked obliquely so as to be adjacent to each other, and the light exit surface 72b "of the light guide plate 72" serves as the light emitting surface. The apex angle θ is 30 ° as in the sixth embodiment. .

  The illuminating device 80 "shown in the present embodiment can be made thinner than the sixth and seventh embodiments, and can be a thin illuminating device with high light utilization and high brightness.

  16 and 17 show an illuminating device 100 according to a ninth embodiment of the present invention.

  The illuminating device 100 is an improvement of the illuminating device 70 shown in FIG. 12, and differs from the illuminating device 70 shown in FIG. 12 in the following points, and has characteristics based on this different configuration. .

  (1) Configuration of the diffusion pattern 101 on the back surface of the light guide plate.

  (2) A configuration in which a special linear prism plate 102 is disposed between the light guide plate and the normal linear prism plate.

  16 and 17, reference numeral 105 denotes a fluorescent tube as a linear light source. A light guide plate 106 has an incident surface 106a, a horizontal back surface 106b, and an output surface 106c. 106d is a tip. In the light guide plate 106, the exit surface 106c, the thickness t of which decreases with increasing distance from the entrance surface 106a, is an inclined surface that forms an angle θ with respect to the back surface 106b. The light guide plate 106 has a wedge shape and has a right triangle. Reference numeral 107 denotes a reflection plate, which is disposed below the light guide plate 106. A reflecting mirror 108 surrounds the fluorescent tube 105. Reference numeral 109 denotes a space, which exists above the inclined exit surface 106c of the light guide plate 106 and ahead of the tip 106d.

  Reference numeral 110 denotes a normal linear prism plate, which is disposed above the light guide plate 106, and has a space 109 formed therebelow. As shown in FIG. 18, the normal linear prism plate 110 has a structure in which roof-shaped linear prisms 111 having an apex angle of 90 degrees are aligned. As shown in FIG. 18, the normal linear prism plate 110 is oriented so that the surface on which the linear prism 111 is formed is the upper surface, and the longitudinal direction of the linear prism 111 is perpendicular to the fluorescent tube 105 (line 112) (indicated by 112) in a clockwise direction. As shown in FIG. 18, the normal linear prism plate 110 acts so that incident light 113 having a large spread is condensed in the direction of the normal line 114 of the normal linear prism plate 110 and emitted. The degree of condensing of the emitted light 115 is about ± 40 degrees.

  116 is a diffusion sheet, which is usually disposed on the upper surface side of the linear prism plate 110 and diffuses light from the normal linear prism plate 110. The upper surface of the diffusion sheet 116 becomes the light emitting surface 117 of the lighting device 100.

  Next, a characteristic configuration of the lighting device 100 will be described.

  First, the diffusion pattern 101 will be described.

  The diffusion pattern 101 has a configuration in which small portions to which white ink is applied, that is, white ink application small sections 120 as diffusion elements are arranged in a predetermined pattern. The light beam incident on the white ink application small section 120 is diffused. As shown by the line I in FIG. 19, the white ink application small section 120 is formed at a particularly high density in the vicinity of the incident surface 106 a in the back surface 106 b of the light guide plate 106. In other words, the white ink application small section 120 is weighted so that the printing area is particularly large in the vicinity of the incident surface 106 a of the light guide plate 106. The diffusion pattern 101 acts to diffuse a large amount of light particularly in the vicinity of the incident surface 106a.

  Next, the special linear prism plate 102 will be described.

  As shown in FIG. 20, the special linear prism plate 102 includes three roof-shaped linear prisms 121 having an apex angle of 140 degrees, and a roof-shaped linear prism 122 having an apex angle of 70 degrees. It has a structure that is aligned at one rate. As shown in FIGS. 16 and 17, the special linear prism plate 102 is oriented so that the surface on which the linear prisms 121 and 122 are formed is the lower surface, and the longitudinal direction of the linear prism 121 (122) is the above-described direction. The direction perpendicular to the line 112, that is, the direction parallel to the fluorescent tube 105 is provided above the light guide plate 106 and below the normal linear prism plate 110. An air layer 129 exists between the normal linear prism plate 110 and the special linear prism plate 102.

  As shown in FIG. 20, the linear prism 122 having an apex angle of 70 degrees acts to totally reflect the incident light beam 123 and transmit it upward as indicated by reference numeral 124. The linear prism 121 having an apex angle of 140 degrees is incident so that the incident light beam 125 is incident on the upper surface 102a of the special linear prism plate 102 at a critical angle or more in the linear prism 121, and the incident light beam 126 is incident. A light beam 127 reflected by the upper surface 102a and totally reflected by the upper surface 102a is emitted from the linear prism plate 102 obliquely downward toward the center of the illuminating device 100 into the space 109 as indicated by reference numeral 128. It returns to the part 109, that is, acts to propagate the light in the surface direction of the special linear prism plate 102.

  Here, the linear prism 121 is oriented in parallel with the fluorescent tube 105. For this reason, the light 128 is efficiently directed toward the center of the lighting device 100. That is, the special linear prism 102 is set so that the longitudinal direction of the linear prism 121 (122) is parallel to the fluorescent tube 105 in order to improve the light propagation property toward the center of the illumination device 100.

  Next, operation | movement of the illuminating device 100 which becomes the said structure is demonstrated with reference to FIG.

  In FIG. 21, the arrow indicates a light beam, and the thickness of the arrow indicates the amount of light. The thicker the arrow, the greater the amount of light. Light 130 from the fluorescent tube 105 enters the light guide plate 106 from the incident surface 106 a and travels toward the tip 106 d of the light guide plate 106. Due to the distribution of the diffusion pattern 101, most of the light incident on the light guide plate 106 is diffused in the vicinity of the incident surface 106a. Accordingly, a large amount of light 131 is emitted from the vicinity of the incident surface 106a in the emission surface 106b. The remaining light 132 propagates toward the tip 106d of the light guide plate 106. Since the amount of light 132 is originally small and is diffused even during propagation and the lights 133 and 134 are emitted from the exit surface 106b, the light directed to the tip 106d is reduced as indicated by reference numerals 135 and 136, and is less than that of the tip 106d. The quantity of the emitted light 137 is reduced. As a result, the inconvenience that the portion of the light emitting surface 117 corresponding to the tip 106d of the light guide plate 106 becomes particularly bright is solved.

  The light 131 is incident on the special linear prism plate 102. Of the light incident on the special linear prism plate 102, only a part of the light 140 is transmitted and emitted upward, and the remaining light 141 is reflected and returned to the space portion 109.

  As for the lights 133 and 134, only a part of the lights 142 and 143 are transmitted through the special linear prism plate 102 and emitted upward, and the remaining lights 144 and 145 are reflected and enter the space 109. Returned. The light 141, 144, 145 returned to the space 109 is reflected by the emission surface 106 c of the light guide plate 106, etc., is incident on the special linear prism plate 102 again, and part of the light is transmitted upward. The light is emitted and the rest is reflected and returned to the space 109 again.

  The above operation is repeated, and a substantially constant amount of light is emitted from the upper surface 102 a of the special linear prism plate 102 over the entire surface of the special linear prism plate 102. For this reason, as will be described later, the light emitting surface 117 has uniform brightness over the entire surface.

  The light emitted upward from the special linear prism plate 102 is normally incident into the linear prism plate 110, is condensed and emitted in the normal direction, as indicated by reference numeral 145, and is further diffused by the diffusion sheet 116. As indicated by reference numeral 146, the light is emitted from the light emitting surface 117.

  As a result, the light emitting surface 117 of the lighting device 100 does not show a portion having a higher luminance than the periphery thereof in the portion corresponding to the tip 106d of the light guide plate 106, and the portion near the fluorescent tube 105 has a high luminance. The portion does not appear and has a good luminance distribution in which the luminance is substantially constant over the entire surface.

  Next, characteristics of the liquid crystal display device when the above-described illumination device 100 is used as a backlight of a liquid crystal panel will be described.

  In FIG. 17, reference numeral 150 denotes a liquid crystal panel, which is arranged on the upper side of the illumination device 100.

  The liquid crystal panel 150 includes an X-direction display electrode 151 extending in the X direction and a Y-direction display electrode 152 extending in the Y direction.

  In FIG. 17, a line 112 orthogonal to the fluorescent tube 105 extends in the X direction.

  Here, the positional relationship of the linear prisms 111, 121, 122 with respect to the display electrodes 151, 152 when viewed from the front surface of the liquid crystal display device will be described.

  The linear prism 111 and the linear prisms 121 and 122 intersect at an angle (90−α) degrees. For this reason, the linear prism 111 and the linear prisms 121 and 122 hardly interfere with each other, and no moire fringes are generated.

  The linear prism 111 and the display electrodes 151 and 152 intersect at about 45 degrees. For this reason, the linear prism 111 and the display electrodes 151 and 152 do not easily interfere with each other, and moire fringes are not generated.

  Next, a modification of the ninth embodiment will be described.

  The ratio between the linear prism 121 and the linear prism 122 of the special linear prism plate 102 in FIGS. 16 and 17 may be set to a ratio other than 3: 1, such as 4: 1.

  FIG. 22 shows a special linear prism plate 102A in which the ratio of the linear prism 121 to the linear prism 122 is 4: 1.

  This prism plate 102A propagates more light in the surface direction than the prism plate 102 described above.

  Further, instead of the special linear prism plate 102, a special lenticular plate 160 shown in FIG. 23 may be provided with the face of the semi-cylindrical lens facing downward.

  The special lenticular plate 160 has a structure in which a kamaboko-shaped lens 161 having a height of h1 and a radius of r1 is aligned at a ratio of one with respect to three kamaboko-shaped lenses 161 having a height of h1 and a radius of r1. h2> h1, r2> r1.

  As can be seen from the path of the light beam 163, the semi-cylindrical lens 162 acts to transmit the light beam upward. As can be seen from the path of the light beam 164, the semi-cylindrical lens 161 acts to return the light beam downward, that is, to propagate the light toward the surface of the special lenticular plate 160.

  Next, the illuminating device 200 which becomes 10th Example of this invention is demonstrated with reference to FIG.

  In the tenth to twentieth embodiments, the rear surface of the light guide plate is devised to make the luminance distribution uniform.

  In FIG. 24, 201 is a fluorescent lamp as a linear light source. A light guide plate 202 has a back surface 202a and an output surface 202b that are both horizontal, and an incident surface 202c and a tip surface 202d that are both vertical. Reference numeral 203 denotes a reflection plate, which is disposed on the back surface 202 a side of the light guide plate 202. Reference numeral 204 denotes a reflection surface, which is an upper surface of the reflection plate 203. A reflecting mirror 205 surrounds the fluorescent lamp 201. Reference numeral 206 denotes a light emitting surface of the lighting device 200. Reference numeral 207 denotes a groove that forms a main part of the present invention. The groove 207 extends on the back surface 202a of the light guide plate 202 in a direction parallel to the incident surface 202c (in the drawing, a direction perpendicular to the paper surface). Yes. The groove 207 is aligned with the pitch P1 in the central portion 202a-1 of the back surface 202a, and the pitch becomes narrower as it deviates from the central portion 202a-1, and the portion near the incident surface 202a-2 and the portion near the tip surface 202a-3 is arranged in a distribution in which the pitch P2 is narrower than the pitch P1.

  The groove 207 has a triangular shape and includes two inclined planes 208 and 209 as shown in an enlarged view in FIG. The inclined planes 208 and 209 are both inclined at a predetermined angle θ with respect to the horizontal plane. The angle θ is about 30 degrees, and is an angle that does not return incident light to the fluorescent lamp 201 side.

  Here, the operation of the groove 207 will be described.

  A part of the light emitted from the fluorescent lamp 201 and incident into the light guide plate 202 from the incident surface 202 c is directed to the groove 207. The light traveling toward the groove 207 can be classified into three types of light rays 210, 211, and 212 depending on the angle at which it strikes the inclined plane 208. The light ray 210 is totally reflected by the inclined plane 208 and becomes a light ray 210a toward the emission surface 202b. The light beam 211 exits into the groove 207, is reflected by the reflection surface 204 of the reflection plate 203, enters the light guide plate 202 again from the inclined plane 209, and becomes the light beam 211a toward the emission surface 202b. The light ray 212 exits into the groove 207, crosses the groove 207, enters the light guide plate 202 again from the inclined plane 209, becomes a light ray 212a, and travels in the direction of the distal end surface 202d. As described above, the groove 207 acts to efficiently direct the light beam traveling in the light guide plate 202 toward the back surface 202a toward the exit surface 202b.

  Conventionally, as shown in Japanese Patent Laid-Open No. 2-165504, the grooves corresponding to the above-described grooves 207 are arranged at a uniform pitch over the entire bottom surface of the light guide plate, and the inclination of the surfaces constituting the grooves is The condition is that all the light incident on the groove is totally reflected. Therefore, the luminance distribution on the light emitting surface has a tendency that the luminance decreases at a portion near the incident surface 202c and a portion near the tip surface 202d, as indicated by a broken line II in FIG.

  In the present embodiment, since the grooves 207 are arranged in the distribution as described above, the amount of light traveling toward the exit surface 202b is the above in the portion 202a-2 near the entrance surface and the portion 202a-3 near the tip surface. As compared with the conventional example, the luminance of the light emitting surface 206 near the entrance surface and the portion near the tip surface is increased. As a result, the luminance of the light emitting surface 206 of the illuminating device 200 becomes substantially uniform over the entire surface, as indicated by line III in FIG.

  FIG. 26 shows an illumination device 220 according to the eleventh embodiment of the present invention. In the figure, the same parts as those shown in FIG.

  In the light guide plate 202A, the grooves 207 are distributed at the same pitch P3 in the vicinity of the fluorescent lamp 201 on the back surface 202a. .. Are assigned to the groove 207 from the side close to the incident surface 202Ac. The U-shaped reflecting mirror 205A extends to the groove 207-1. 205Aa is an upper cover portion as a reflecting mirror portion, and covers a portion 202Ab-1 corresponding to the groove 207-1 near the incident surface 202Ac in the exit surface 202Ab of the light guide plate 202A. 205Ab is a lower cover portion and covers the groove 207-1 in the back surface 202Aa of the light guide plate 202A. Of the light guide plate 202A, 202A-1 is a light emitting region. Reference numeral 202A-2 denotes a light storage area, which stores light as will be described later. The light 221 emitted from the fluorescent lamp 201 and incident on the light guide plate 202A from the incident surface 202Ac is reflected by the surface of the groove 207-1 as indicated by reference numeral 221a, travels toward the surface 202Ab-1, and enters the surface 202Ab-1. Although it is emitted more, it is reflected by the upper cover portion 205Aa and enters the light guide plate 202A. Even if the light travels toward the back surface 202Aa and is emitted from the back surface 202Aa, it is reflected by the lower cover portion 205Ab, enters the light guide plate 202A again, and travels upward. The light repeats this and proceeds in the direction of the light emitting region 202A-1.

  The portion of the emission surface 202Ab that is not covered by the upper cover portion 205Aa is the effective emission surface 202Ab-2. As in the case of the ninth embodiment, light that is reflected or refracted by the grooves 207-2 to 207-5 and directed upward is emitted to the effective emission surface 202Ab-2. Looking at the portion of the effective emission surface 202Ab-2 closer to the fluorescent lamp 201, light 221b leaked from the light storage region 202A-2 and directed upward is added to the light 222 refracted by the groove 207-2. The amount of light at the part increases. As a result, the luminance of the light emitting surface 206 of the illuminating device 220 is substantially uniform in the vicinity of the fluorescent tube, as indicated by the line IV.

  FIG. 27 shows an illumination device 230 according to an eleventh embodiment of the present invention. This illumination device 230 is a combination of the illumination device 200 of FIG. 24 and the illumination device 220 of FIG. In FIG. 27, parts corresponding to the parts shown in FIGS. 24 and 26 are denoted by the same reference numerals.

  The groove 207-1 and the upper cover portion 205Aa as the reflecting mirror portion form the light accumulation region 202A-2. On the portion of the effective emission surface 202Ab-2 that is closer to the fluorescent lamp 201, the light 222 reflected and refracted by the grooves 207-2 and 207-3 leaks from the light storage region 202A-2 and travels upward 221b. Will be added. Here, since the pitch P2 of the grooves 207-1 and 207-2 is small, the light amount of the light 222 is large. As a result, the luminance of the light emitting surface 206 becomes uniform over the entire surface as indicated by the line V in FIG.

  FIG. 28 shows an illumination device 240 according to a thirteenth embodiment of the present invention. This illuminating device 240 is the structure which changed the light-guide plate 202 among the illuminating devices 200 of FIG. In FIG. 28, parts corresponding to the parts shown in FIG.

  The light guide plate 241 is generally formed by making the light guide plate 202 into a wedge shape in cross section, and has an inclined emission surface 241b and a curved tip surface 241c. Reference numeral 241a denotes a horizontal rear surface on which a groove 207 is formed. Reference numeral 241c denotes a vertical incident surface.

  Here, the reason why the tip surface 241c can be a curved surface is that the exit surface 241b is an inclined surface and the light guide plate 202 has a wedge shape.

  Since the tip surface 241c is a curved surface, the light that propagates in the light guide plate 241 and reaches the tip is less likely to be reflected to the light source side, compared to the case where the tip is a vertical plane as shown in FIG. Most of the light is discharged upward from the tip surface 241c, as indicated by reference numeral 242. Thereby, light is also efficiently emitted from the portion of the light guide plate 241 near the tip, and the luminance of the tip portion of the light emitting surface 243 is increased. The luminance of the light emitting surface 243 is uniform over the entire surface as indicated by the line VI in FIG.

  FIG. 29 shows an illumination device 250 according to a fourteenth embodiment of the present invention. In the figure, parts corresponding to those shown in FIG.

  The lighting device 250 includes a light guide plate 251. As shown in FIG. 30, the light guide plate 251 has a pit group 252 on the back surface 251a. The pit group 252 includes a large number of pits 253. Each pit 253 has a triangular cross section and, like the groove 207 in FIG. 24, propagates through the light guide plate 251 and directs the light reaching the back surface 251a toward the exit surface 251b. The pit group 252 includes a pit row 254-1 composed of arranged pitches 253-1 to 253-4, a pit row 254-2 composed of arranged pits 253-5 to 253-7, and arranged pits 253-8 to 253- 11 pit rows 254-2 are arranged in parallel, and pits are arranged in a staggered manner between adjacent pit rows. As a result, as shown in FIG. 24, the amount of light directed from the back surface 251a side to the emission surface 251b is made more uniform over the entire back surface as compared with the case where the groove 207 is formed on the back surface.

  As a result, the light emitting surface 255 of the illumination device 250 can suppress uneven brightness corresponding to the groove streaks as compared with the illumination device 200 of FIG. 24, and uniform luminance over the entire surface as shown by line VII in FIG. Have a distribution.

  FIG. 31 shows an illumination device 260 according to the fifteenth embodiment of the present invention. In the figure, parts corresponding to those shown in FIG.

  The lighting device 260 includes a light guide plate 261. As shown in FIGS. 32 and 33, the light guide plate 261 has a groove group 262 having a triangular cross section on the back surface 261a. The groove group 262 includes a groove 262a that forms an acute angle α1 with respect to a line 264 orthogonal to the axis 263 of the fluorescent lamp 201, and a groove 262b that forms an obtuse angle α2 with respect to the line 264. The groove 262a and the groove 202b intersect at many points. For this reason, a groove streak is hard to appear compared with the illuminating device 200 of FIG. 24 where the groove | channel is distribute | arranged in parallel. Accordingly, the illumination device 260 has a uniform luminance distribution over the entire surface, as indicated by a line VIII in FIG.

  FIG. 34 shows a lighting device 270 according to a sixteenth embodiment of the present invention. In the figure, parts corresponding to those shown in FIG.

  The lighting device 270 includes a light guide plate 271. The light guide plate 271 has a groove group 271 on the back surface 271a. The groove group 271 includes grooves 272 to 277. The size of the grooves 272 to 277 increases as the distance from the fluorescent lamp 201 approaches. The pitch P4 of the grooves 272 to 277 is constant and smaller than the pitch P1 in FIG. Therefore, the illuminating device 270 has less groove streaks and the same amount of emitted light as compared with the device 200 of FIG. 24, and has a uniform luminance distribution over the entire surface as shown by the line IX in FIG. Have.

  FIG. 35 shows an illumination device 280 according to a seventeenth embodiment of the present invention. In the figure, parts corresponding to those shown in FIG.

  The lighting device 280 includes a light guide plate 281. As shown in FIG. 36, the light guide plate 281 has a pit group 282 on the back surface 281a. The pit group 282 includes a large number of pits 283. Each pit 283 has a triangular cross section and, like the groove 207 in FIG. 24, propagates through the light guide plate 281 and directs the light reaching the back surface 281a toward the exit surface 281b. The pit group 282 includes an oblique pit row 284 on the lower right in FIG. 36 and an oblique pit row 285 on the upper right in which pits 283 are arranged. The pit row 284 intersects the pit row 285. As a result, as shown in FIG. 24, the amount of light directed from the back surface 281a side to the emission surface 281b is made more uniform over the entire back surface as compared with the case where the groove 207 is formed on the back surface.

  As a result, the light emitting surface 286 of the lighting device 280 can suppress uneven luminance corresponding to the groove streaks compared to the lighting device 200 of FIG. 24, and uniform luminance over the entire surface as indicated by a line X in FIG. 35. Have a distribution.

  FIG. 37 shows an illumination device 290 according to an eighteenth embodiment of the present invention. In the figure, parts corresponding to those shown in FIG.

  The lighting device 290 includes a light guide plate 291. The light guide plate 291 has a groove 292 having a triangular cross section on the back surface 291a. The angle θ10 with respect to the extended surface of the opposite surface 291a of the groove 292 is set to be considerably smaller than the angle θ11 in FIG. When the angle θ10 is small, the ability of the groove 292 to direct light toward the emission surface 291b is small. Thus, by changing the angle θ10 of the groove 292, the amount of light emitted from the light exit surface 291b can be changed.

  FIG. 38 shows an illumination apparatus 300 according to the nineteenth embodiment of the present invention. The light guide plate 310 has a U-shaped groove 302 on the back surface 301a.

  FIG. 39 shows an illuminating device 310 according to a twentieth embodiment of the present invention. The lighting device 310 includes a light guide plate 311 and a reflection plate 312. The light guide plate 311 has a back surface 311a having grooves 318 having a uniform pitch. Reference numeral 312 denotes a reflecting plate having a large number of protrusions 313 on the upper surface facing the back surface 311a. The ridge 313 reflects the light 314 leaked from the groove 318 on the back surface 311a of the light guide plate 311 and re-enters the light guide plate 311 as indicated by reference numeral 314a to be light directed toward the exit surface 311b.

  The ridges 313 are aligned at the pitch P10 with respect to the central portion 314, and the pitch becomes narrower as it deviates from the central portion 314. The portion 315 closer to the incident surface 311c and the portion 316 closer to the tip surface 311d are narrower than the pitch P11. It is arranged in a distribution aligned with P11.

  Of the light leaking from the groove 318 on the back surface 311a of the light guide plate 311, the light leaking from the vicinity of the incident surface 311c and the light leaking from the vicinity of the tip surface 311d are compared with the light leaking from the central portion. The light is returned more efficiently into the light guide plate 311 and emitted from the light emitting surface 317. For this reason, the luminance distribution of the light emitting surface 317 is substantially uniform over the entire surface as shown by the line XI in FIG.

It is a principle block diagram of the illuminating device relevant to this invention. It is operation | movement explanatory drawing of the illuminating device relevant to this invention. It is a figure which shows the 1st Example of the illuminating device which becomes this invention. It is a figure which shows the 2nd Example of the illuminating device which becomes this invention. It is a figure which shows the 3rd Example of the illuminating device which becomes this invention. It is a figure which shows the 4th Example of the illuminating device which becomes this invention. It is FIG. (1) which shows the directional characteristic of a light-guide plate. It is FIG. (2) which shows the directional characteristic of a light-guide plate. It is FIG. (The 3) which shows the directional characteristic of a light-guide plate. It is FIG. (4) which shows the directional characteristic of a light-guide plate. It is FIG. (5) which shows the directional characteristic of a light-guide plate. It is a figure which shows the 5th Example of the illuminating device which becomes this invention. It is a figure which shows the 6th Example of the illuminating device which becomes this invention. It is a figure which shows the 7th Example of the illuminating device which becomes this invention. It is a figure which shows 8th Example of the illuminating device which becomes this invention. It is a figure which shows 9th Example of the illuminating device which becomes this invention. It is a disassembled perspective view of the illuminating device of FIG. It is the elements on larger scale of the normal linear prism board in FIG.16 and FIG.17. It is a figure explaining the spreading | diffusion pattern of the back surface of a light-guide plate. It is the elements on larger scale of the special linear prism board in FIG.16 and FIG.17. It is a figure explaining operation | movement of the illuminating device of FIG. It is a figure which shows the modification of a special linear prism board. It is the elements on larger scale of a special lenticular board. It is a figure which shows 10th Example of the illuminating device by this invention with the luminance distribution. It is a figure explaining the effect | action of a groove | channel in FIG. It is a figure which shows 11th Example of the illuminating device which becomes this invention together with the luminance distribution. It is a figure which shows 12th Example of the illuminating device which becomes this invention together with the luminance distribution. It is a figure which shows 13th Example of the illuminating device which becomes this invention together with the luminance distribution. It is a figure which shows 14th Example of the illuminating device which becomes this invention together with the luminance distribution. It is a figure which shows arrangement | positioning of the pit group of the back surface of the light-guide plate in FIG. It is a figure which shows 15th Example of the illuminating device which becomes this invention together with the luminance distribution. It is the figure which looked at the light-guide plate in FIG. 31 from the back side. It is a perspective view which expands and shows a part of back surface of the light-guide plate of FIG. It is a figure which shows 16th Example of the illuminating device which becomes this invention together with the luminance distribution. It is a figure which shows 17th Example of the illuminating device which becomes this invention together with the luminance distribution. It is the figure which looked at the light-guide plate in FIG. 35 from the back side. It is a figure which shows 18th Example of the illuminating device which becomes this invention. It is a figure which shows 19th Example of the illuminating device which becomes this invention. It is a figure which shows 20th Example of the illuminating device which becomes this invention together with the luminance distribution. It is a figure which shows the conventional illuminating device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 2 Light guide plate 2a Incidence surface 2b Back surface 2c Output surface 3 Reflection surface 3a Side wall surface 4 Light emission surface 5 Space part 6 Reflector 7 Propagation light 8 Output light 10 Illumination device 100 Illumination device 101 Diffusion pattern 102,102A Special linear prism plate 102a upper surface 105 fluorescent tube 106 light guide plate 106a incident surface 106b rear surface 106c emission surface 106d tip 107 reflecting plate 108 reflecting mirror 109 space portion 110 normal linear prism plate 111 linear prism 112 line in a direction orthogonal to the fluorescent tube 113 incident light 114 method Line 115 Outgoing light 116 Diffusion sheet 117 Light emitting surface 120 White ink application small section 121 Linear prism with apex angle 140 degrees 122 Linear prism with apex angle 70 degrees 123 Incident light 124 Emission light 125 Incident light 126 Incident light 128 Total reflection Line 128 Light rays returned to the space portion 129 Air layer 131 A large amount of light diffused when entering the light guide plate 141, 144, 145 Light returned to the space portion 150 Liquid crystal panel 151 X direction display electrode 152 Y direction display Electrode 160 Special lenticular plate 161 Spotted lens 162 Spotted lens 163, 164 Light beam 200, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310 Illuminating device 201 Fluorescent lamp 202, 202A, 241, 251 , 261, 271, 281, 291, 301, 311 Light guide plate 202 a Rear surface 202 a-1, 314 Central portion 202 a-2, 315 Near the incident surface 202 a-3, 316 Near the tip surface 202 b Emission surface 202 c Incident surface 202 d Tip surface 203, 312 Reflection surface 204 Reflecting surface 205 Reflecting mirror 205Aa Upper covering portion 205Ab Lower covering portion 206 Light emitting surface 207 Groove 208, 209 Inclined plane 210, 211, 212 Light beam 241 Inclined emitting surface 241c Tip surface 242 Light emitted from tip surface 252 Pit group 253 Pits 254-1, 254-2, and 254-3 having a triangular cross section 262 pit group 263 groove group 263 fluorescent lamp axis 264 line perpendicular to fluorescent lamp axis 272 to 277 groove 282 pit group 283 pit 284 285 pit array 286 Light emitting surface 302 U-shaped groove 313 Projection

Claims (3)

A plurality of unit units including a light source and a light guide plate are provided,
The light guide plate includes an incident surface on which a light beam emitted from the light source is incident, a reflective surface that reflects the incident light beam, a side surface that is substantially parallel to the reflective surface, and an output beam that emits the incident light beam. And the reflective surface is inclined with respect to the exit surface,
Each of the light guide plates has the same shape,
Each of the unit units is arranged in the same direction,
The light source of the second unit unit adjacent to the first unit unit is disposed behind the emission surface of the first unit unit, and the first unit unit and the second unit unit are Is a lighting device adjacent to each other without providing a step .   The illuminating device of Claim 1 provided with a diffusion sheet in the said output surface side of the said light-guide plate.   A liquid crystal display device comprising the illumination device according to claim 1.

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